Resistor unit and method of forming the same



Dec. 31, 1929. L. E. POWER 1,741,582

RESISTOR UNIT AND METHOD OF FORMING THE SAME File 28, 1927 2 Sheets-Sheet l Ldu1"@m:@ E-PD EP Dec. 31, 1929. 1.. E. POWER 1,741,582

RESISTOR UNIT AND METHOD OF FORMING THE SAME Filed Oct- 28, 192 2 Sheets-Sheet 2 I Jmumnc 51 mm;

/ of the elements may And a still the entire unit with a stifienin Patented Dec. 31, 1929 IUNITED'QS-TATES. PATENT OFFICE LAURENCE E. POWER, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO THE RELIANCE COMPANY, OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN RESISTOR UNIT AND METHOD OF FORMING THE SAME Application am October as, 19 2?. .Serial no. 225,409.

5 and other apparatus and the method of forming the same, and has as an object the provision of an improved resistor unit which provides different resistances in a single unit.

Another'object of this invention resides in 10 the provision of an improved unit of the character described having a glurality of resistor elements of predetermme values and secured end to end with terminals between the adja cent elements whereb ll or any one or more included in a circuit .accordin to the'resistanceit is desired to impose in t e circuit.

It is a further object of this invention to provide an improved resistor unit having a 20 plurality of centrally bored resistor units adapted to be arranged end to end with terminal members therebetween and means passing through the bores of the units to connect them. I

further object of'this invention resides in the provision of an improved method of forming resistor units by placing elements of predetermined values end to end with tap offs therebetween, in impregnating agent, such as a phenol condensation varnish and baking the same, and in further impregnating the unit with parafiin should it be desired.

With the above and other objects in view.

which will appear as the description proceeds, my invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed inventionv may bemade as come within the scope of the claims.

In the accompanying drawings, I have illustrated several complete examples of the physical embodiment of my invention constructed according to the best modes I have so far devised for'the practical application of the principles thereof, and in which:

Figure 1 is a side view, partly in elevatlon and partly in section, of a resistance unit embodying my invention;

Figure 2 is a .transverse sectional view.

taken through Figure 1 on the plane of the hue 2-2;

Figure 3 is a side elevational view of a sli hty modified resistor unit;

, igure 4 is a erspe'ctive view, with parts broken away and fied form of resistor unit embodying this invention; v i

Figure 5 is an enlarged, fragmentary perspective view of one end portion of the unit illustrated in Figure 4 with the resistor elements, end caps and terminal members in spaced relation;

Figure 6 is a diagrammatic view illustrating the manner of cementing the elements,

and terminal members under pressure in the presence of heat; and i i Figure 7 is an enlarged view illustrating one manner of obtaining pressure on-a unit atter it has been assembled.

Referring now more particularly to the ac companying drawings, in which llke numerals designate like parts throughout the several views, 5, 6, 7 and 8 represent independent resistance elements of predetermined values' obtained in a suitable manner and arranged end to end with terminal members 9 therebetween to facilitate the inclusion of the elements in suitable circuits, not shown.

In the embodiment illustrated in Figures 1, 2 and 3, the resistor elements have central bores 10 extending throughout their lengths and likewise the inner enlarged portions 11 in section, of another Inodi-v of the terminals are centrally bored, as at 12,

to accommodate a clamping rod 13 which passes therethrough and is threaded at its' vide an air space surrounding rod 13 so that f the various'units are insulated therefrom and.

if desired, the rod 13 maybe covered witha 7 spring washer 17 is provided'to supply any give that may be necessary in the contraction and expansion of the unit.

In that form of my invention illustrated in Figures 4 to 7, inclusive, the rod 13 is eliminated and the various elements are secured in end to end relation with the terminals therebetween by a suitable cement having the desired tenacity and conductive qualities and preferably consisting of a mixture of varnish and a powdered conductor, such as graphite, gas black, or copper powder mixed in the desired proportions. The resistor elements are solid and the cement is applied to the ends thereof and the assembly is disposed in a chute or trough 20 with caps or end members 21 covering the outermost terminals and pressure is applied in a suit able manner and as by a weight or other means 22, shown diagrammatically in Figures 6 and 7. The unit with the pressure applied thereto is then preferably placed in an oven 23 or otherwise subjected to heat until the cement sets. The end members 21 may be formed of composition having the desired conductive characteristics'or of metal and provide means for mounting the unit.

- If desired, the unit may then be wrapped with a suitable covering 24, impregnated with a stifiening agent, such as a phenol condensation varnish and then baked. The unit may also be impregnated with parafiin or other substance to exclude moisture.

The respective resistor elements are molded and their resistance values determined in any desired manner. a

It will thus be readily apparent that with a unit of the character described, it is possible to obtain within a circuit a resistance equal to the combined values of all the elements or a resistance equal to any one or more of the elements and the respective elements ma be of the same resistance values or of di erent values depending upon the specific needs for which the units are mann factured.

What I claim as my invention is:

1. A resistor unit consisting of end to end arranged sections molded from a common composition of materials and of varied lengths to provide a difl'erence in resistance values, terminal tap ofli's disposed between the sections, and means cementing the sections to opposite sides of the terminal tap oils and t'oeach other through apertures in the terminal tap offs.

2. The method of forming a resistor unit which consists in forming independent resistor'elements of predetermined resistance values, in securing the elements in end to end relation with tap oils therebetween, and in covering the unit and impregnating the covering with a stiffening agent.

The method of forming a resistor unitwhich consists in forming independent resistor elements of predetermined resistance values, in securing the elements in end to end relation with tap oils therebetween, in covering the unit, and in impregnating the covering with a phenol condensation product.

4. The method of forming a resistor unit which consists in forming independent resistor elements of predetermined resistance values, in securing the elements in end to end relation. with tap offs therebetween, in covering the unit, in impregnating the covering with a phenol condensation product, and" in baking the unit.

5. A resistor unit consisting of end to end arranged elements, terminal tap-offs having apertured portions disposed between the elements, means cementing the elements and tapofls' into aJsingle unit, the cement entering the apertures in the terminal tap-oil's to form a bond directly between adjacent elements through the tap-offs, and a protective covering for the unit providing added rigidity "therefor.

6. A resistor unit consisting of end to end arranged elements, terminal tap-offs, each having an apertured portion corresponding substantially to the cross-section of the elements, means cementingthe elements and tapoffs into a single unit with the apertured portions of the terminaltap-ofls disposed between the elements, the cement having conductive characteristics and enteringdhe apertures in' the terminal tap-offs to form a bond therethrough directly between adjacent elements, and a protective covering for the unit providing added rigidity therefor.

In testimony whereof I have hereunto affixed my signature.

LAURENCE E. POWER. 

